<abstract xmlns="http://www.w3.org/1999/xhtml">

<sec id="j_jvetres-2022-0071_s_008"><h3>Introduction</h3>
<p>Small ruminant lentivirus (SRLV) causes caprine arthritis-encephalitis in goats and maedi-visna disease in sheep. Transmission is <italic>via</italic> ingestion of colostrum and milk from infected dams or long-term direct contact between animals. Lifelong seroconversion can occur several weeks after infection <italic>via</italic> ingestion. However, sub-yearling lambs that ingest contaminated colostrum may be able to clear the infection and become seronegative. Whether a similar phenomenon occurs in goats remains unknown. Therefore, the serological status of goats was studied longitudinally from the moment of natural exposure to colostrum and milk of SRLV-positive dams through the age of 24 months.</p></sec>
<sec id="j_jvetres-2022-0071_s_009"><h3>Material and Methods</h3>
<p>Between February 2014 and March 2017 a dairy goat herd was studied which had been infected with SRLV for more than 20 years and carried maedi-visna virus-like genotype A subtype A17. Thirty-one kids born to dams seropositive for SRLV for at least a year beforehand were followed. They ingested colostrum immediately after birth and then remained with their dams for three weeks. The goats were tested serologically every month using two commercial ELISAs. The clinical condition of the goats was also regularly assessed.</p></sec>
<sec id="j_jvetres-2022-0071_s_010"><h3>Results</h3>
<p>Out of 31 goats, 13 (42%) seroconverted at the age ranging from 3 to 22 months with a median of 5 months. Two goats seroconverted in the second year of life. The other eleven did so before the age of one year; two of these reverted to seronegative status. Only 9 out of 31 goats (29%) seroconverted in the first year of life and remained seropositive. They were early and stable seroreactors to which SRLV was transmitted lactogenically. The age at which they seroconverted ranged from 3 to 10 months with a median of 5 months. In 8 of the 18 persistently seronegative goats, a single isolated positive result occurred. No goats showed any clinical signs of arthritis. The level of maternal antibodies at the age of one week did not differ significantly between the stable seroreactors and the remainder.</p></sec>
<sec id="j_jvetres-2022-0071_s_011"><h3>Conclusion</h3>
<p>Seroconversion appears to occur in less than 50% of goats exposed to heterologous SRLV genotype A <italic>via</italic> ingestion of colostrum and milk from infected dams and is delayed by 3–10 months. The natural lactogenic route of transmission of SRLV genotype A in goats appears to be less effective than this route of genotype B transmission reported in earlier studies.</p></sec></abstract>

Introduction
Small ruminant lentivirus (SRLV) causes caprine arthritis-encephalitis in goats and maedi-visna disease in sheep. Transmission is via ingestion of colostrum and milk from infected dams or long-term direct contact between animals. Lifelong seroconversion can occur several weeks after infection via ingestion. However, sub-yearling lambs that ingest contaminated colostrum may be able to clear the infection and become seronegative. Whether a similar phenomenon occurs in goats remains unknown. Therefore, the serological status of goats was studied longitudinally from the moment of natural exposure to colostrum and milk of SRLV-positive dams through the age of 24 months.
Material and Methods
Between February 2014 and March 2017 a dairy goat herd was studied which had been infected with SRLV for more than 20 years and carried maedi-visna virus-like genotype A subtype A17. Thirty-one kids born to dams seropositive for SRLV for at least a year beforehand were followed. They ingested colostrum immediately after birth and then remained with their dams for three weeks. The goats were tested serologically every month using two commercial ELISAs. The clinical condition of the goats was also regularly assessed.
Results
Out of 31 goats, 13 (42%) seroconverted at the age ranging from 3 to 22 months with a median of 5 months. Two goats seroconverted in the second year of life. The other eleven did so before the age of one year; two of these reverted to seronegative status. Only 9 out of 31 goats (29%) seroconverted in the first year of life and remained seropositive. They were early and stable seroreactors to which SRLV was transmitted lactogenically. The age at which they seroconverted ranged from 3 to 10 months with a median of 5 months. In 8 of the 18 persistently seronegative goats, a single isolated positive result occurred. No goats showed any clinical signs of arthritis. The level of maternal antibodies at the age of one week did not differ significantly between the stable seroreactors and the remainder.
Conclusion
Seroconversion appears to occur in less than 50% of goats exposed to heterologous SRLV genotype A via ingestion of colostrum and milk from infected dams and is delayed by 3–10 months. The natural lactogenic route of transmission of SRLV genotype A in goats appears to be less effective than this route of genotype B transmission reported in earlier studies.

Longitudinal study on seroreactivity of goats exposed to colostrum and milk of small ruminant lentivirus–infected dams

Journal of Veterinary Research

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Introduction
Small ruminant lentivirus (SRLV) causes caprine arthritis-encephalitis in goats and maedi-visna disease in sheep. Transmission is via ingestion of...

Longitudinal study on seroreactivity of goats exposed to colostrum and milk of small ruminant lentivirus–infected dams

Publié en ligne: 26 déc. 2022

Pages: 511 - 521

Reçu: 13 sept. 2022

Accepté: 07 déc. 2022

DOI: https://doi.org/10.2478/jvetres-2022-0071

Mots clés
caprine arthritis-encephalitis, colostral antibodies, humoral immunity, maternal antibodies, seroconversion

© 2022 J. Kaba et al. published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Longitudinal study on seroreactivity of goats exposed to colostrum and milk of small ruminant lentivirus–infected dams

Publié en ligne: 26 déc. 2022

Pages: 511 - 521

Reçu: 13 sept. 2022

Accepté: 07 déc. 2022

DOI: https://doi.org/10.2478/jvetres-2022-0071

Mots cléscaprine arthritis-encephalitis, colostral antibodies, humoral immunity, maternal antibodies, seroconversion

© 2022 J. Kaba et al. published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Mots clés
caprine arthritis-encephalitis, colostral antibodies, humoral immunity, maternal antibodies, seroconversion